Cosmetic composition in the form of a soft paste and process for preparation of same

ABSTRACT

A cosmetic composition which is presented in the form of a soft paste, which is capable of being used as lipstick and comprising a fatty phase in which waxes are present. A process for the preparation of this composition is also disclosed.

[0001] The present invention is directed to a composition provided inthe form of a soft paste, in particular to a cosmetic composition whichcan be used for making up the lips, or as a composition for treating thehair and/or the lips.

[0002] Cosmetic compositions which can be applied to the lips astreatments or make-up products, such as lipsticks, generally containfatty substances and waxes, and optionally contain additives andpigments. Such compositions which are presented in the form of a softpaste and which are capable of being applied after collecting with theaid of an applicator, for example a brush, are in particular known.

[0003] These compositions may contain waxes which confer on them notablequalities with regard to the consistency, unctuosity and retention ofthe applied film.

[0004] In order to introduce relatively large quantities of waxes intothese compositions, a preparation process was proposed which consistedof preparing the mixture of the constituents, heating the mixture to atemperature where the waxes are at least partially melted, and thensubjecting the mixture to a blending operation during at least part ofits cooling.

[0005] Crystallization of the waxes in a form which allowed theproduction of a soft and easily removable paste was thus observed.

[0006] It was found, however, that some waxes did not make it possibleto obtain a cosmetic composition having optimum and constant cosmeticqualities during their storage, in particular when this storage wasperformed, even partially, at a temperature greater than a customarytemperature of the order of 20-25° C.

[0007] Indeed, depending on the nature of the waxes present in thecomposition, it was possible to observe, in some cases, a modificationof the viscosity of the composition which could result in substantialhardening of the composition and in problems of application.

[0008] An object of the present invention is to overcome thesedisadvantages and to provide a cosmetic composition having optimumcosmetic qualities during the whole of its storage, inter alia, aviscosity which is practically constant over time, regardless of thetemperature, or the temperature changes, to which it is subjected.

[0009] One subject of the present invention is therefore a cosmeticcomposition provided in the form of a soft paste and comprising a fattyphase in which one or more waxes are present, the composition beingcharacterized in that at least 95% of the waxes have a temperature atthe onset of melting which is greater than or equal to 50° C.

[0010] Another subject of the invention is a process for the preparationof such a cosmetic composition, in which at least a portion of thevarious constituents of the composition, including the waxes, is heatedto a temperature at which the waxes melt at least partially. Theremainder of the constituents are added where appropriate and then themixture obtained is blended during at least part of its cooling.

[0011] The present invention allows the production of compositions whichremain stable over time, that is to say, whose viscosity remainspractically constant. These compositions possess a novel soft textureand exhibit, after application, high retention and high brilliance.

[0012] The composition according to the invention therefore comprises afatty phase in which one or more waxes may be present, it beingnecessary for at least 95% of the waxes to have a temperature at theonset of melting which is greater than or equal to 50° C.

[0013] “Temperature at the onset of melting” is understood in thepresent description to mean the temperature at which a wax begins tomelt.

[0014] This temperature can be determined by DTA (differential thermalanalysis) which makes it possible to obtain the thermogram (or themelting curve) of the wax considered. The temperature at the onset ofmelting corresponds to the temperature at which a notable change inslope can be observed in the thermogram. The melting point, for itspart, represents the minimum point of the thermogram.

[0015] Without being limited by the present explanation, it can beassumed that the change in viscosity observed during the storage of somecosmetic compositions is linked to the modification in the form in whichthe waxes crystallize.

[0016] Indeed, during the manufacture of the composition of the presentinvention, the waxes are crystallized in a certain form which will allowthe production of a soft paste.

[0017] During a substantial rise in temperature during their storage,the waxes may melt at least partially, and then recrystallize in a formdifferent from the initial crystalline form. This second form no longerallows a soft paste to be obtained but is capable of leading to a pastewith a higher viscosity and therefore with a more rigid consistency.

[0018] Thus, by choosing at least 95% of the waxes present in thecomposition from those waxes having a temperature at the onset ofmelting greater than or equal to 50° C., a composition can be obtainedwhose viscosity remains constant. Preferably, waxes are used whosetemperature at the onset of melting is greater than 65° C. It is alsopreferable to choose 100% of the waxes from those whose temperature atthe onset of melting is greater than or equal to 50° C.

[0019] The waxes capable of being used in the present invention, that isto say which make it possible to maintain a viscosity of the cosmeticcomposition constant, may be of any type, in particular, of inorganic,animal, plant or synthetic origin.

[0020] There may preferably be mentioned Carnauba wax, some polyethylenewaxes, and some microcrystalline waxes, such as that sold by Tisco underthe name “Tisco Wax 88”.

[0021] These waxes may be used alone or in the form of a mixture.

[0022] These waxes may also be used in a mixture with waxes whosetemperature at the onset of melting is less than 50° C.; it beingunderstood that these second waxes cannot represent more than 5% byweight of the total waxes.

[0023] The composition according to the invention preferably comprises,in total, 10-60% by weight of wax relative to the final weight of thecomposition. More preferably, the composition comprises 15-35% by weightof wax relative to the final weight of the composition.

[0024] The fatty phase may, in addition, comprise other fattyconstituents such as oils. There may preferably be mentioned:

[0025] mineral oils such as paraffin oil or liquid paraffin;

[0026] animal oils such as perhydrosqualene or arara oil;

[0027] vegetable oils such as sweet almond, calophyllum, palm, castor,avocado, jojoba, olive or cereal germ oil;

[0028] esters of lanolic acid, oleic acid, lauric acid, stearic acid ormyristic acid, for example;

[0029] alcohols such as oleyl alcohol, linoleyl or linolenyl alcohol,isostearyl alcohol or octyl dodecanol;

[0030] acetylglycerides, octanoates, decanoates or ricinoleates ofalcohols or of polyalcohols.

[0031] These fatty constituents preferably represent 40-90% by weight ofthe composition, and more preferably 65-85% by weight of thecomposition.

[0032] In a known manner, there may be added to the compositionaccording to the invention a pulverulent colouring agent such as carbonblack, chromium or iron oxides, ultramarines, manganese pyrophosphate,ferric blue, titanium dioxide, pearlescent agents which are generallyused in the form of a mixture with coloured pigments or-certain organiccolorants which are generally used in the form of a mixture withcoloured pigments or which are commonly used in the cosmetic industry.

[0033] These colouring agents are preferably present in a quantity of 0to 20% relative to the total weight of the composition.

[0034] Inorganic or organic pulverulent fillers may also preferably beadded in a quantity of 0 to 40% relative to the total weight of thecomposition.

[0035] These pulverulent fillers may preferably be chosen from talc,micas, kaolin, zinc or titanium oxides, calcium or magnesium carbonates,silica, spheric titanium dioxide, glass and ceramic beads, metallicsoaps derived from carboxylic acids having 8-22 carbon atoms,nonexpanded synthetic polymer powders, expanded powders and powders ofnatural organic compounds such as cereal starches, crosslinked orotherwise.

[0036] There may also preferably be added any additive customarily usedin the cosmetic industry, such as antioxidants, perfumes, preservatives,as well as cosmetic and/or pharmaceutical active agents such as vitaminderivatives, essential fatty acids, sphingocerils, fat-solublesunscreens, anti-inflammatory agents or oily plant extracts, or evenfat-soluble polymers, and/or silicone oils and/or gums such asdimethylpolysiloxanes. These additives are preferably present in anamount of 0-10% by weight relative to the total weight of thecomposition.

[0037] In order to prepare the composition according to the invention,it is possible to first prepare a premix comprising at least a portionof the various constituents of the composition, including at least thewax according to the invention, to heat this premix at a temperature atwhich the wax melts at least partially, to add, where appropriate, theremainder of the constituents, and then to blend the mixture obtainedduring at least part of its cooling down to room temperature. It wasindeed found that when the mixture is blended during at least part ofits cooling, so as to create shearing regions, a composition is obtainedwhich is presented in the form of a homogeneous and soft paste. It wouldseem, however, without being limited to this explanation, that underthese conditions, the wax crystallizes in the form of fine crystals,which would explain that the composition remains in the form of a softpaste.

[0038] The heating operation may be carried out according to any knowntechnique. The blending operation may be carried out, for example, in aroll mill incorporating two rolls rotating in opposite directionsbetween which the paste passes, or alternatively in a mixer-extruderwhich makes it possible to obtain a paste of highly constant quality ina reproducible manner. Furthermore, it is possible, by adapting theoutlet die of the mixer-extruder, to package the composition on-line atthe outlet of the die.

[0039] In a preferred embodiment of the invention, the mixing, heatingand/or blending/shearing, or even cooling, operations are performed inone or more extruders arranged in succession one after the other; morepreferably, the operations are performed in a single twin-screwextruder.

[0040] Indeed, the composition obtained after extrusion has a specialsmoothness, and offers some sensation of sliding when it is applied tothe skin; while avoiding the appearance and the sensation of oily fat.

[0041] The conditions under which the extrusion may be carried out aredescribed in Patent Application FR-A-2715306, whose disclosure is fullyincorporated in the present application by reference.

[0042] A composition for topical use is thus obtained which may beapplied to the skin and/or to the lips as a make-up product, a lipstickfor example, or as a treatment product.

[0043] The composition of the invention is in the form of a soft paste.The viscosity of the composition of the invention can be measured. Thisis not the case, for example, for compositions in the form of a stick.

[0044] The dynamic viscosity, at 25° C., preferably ranges from 3 to 35Pa.s, measured with the aid of a CONTRAVES TV rotational visometer,equipped with an MS-R4 moving body, at a frequency of 60 Hz.

[0045] The invention is illustrated in greater detail in the followingexamples, in which the percentages are given by weight relative to thecomposition.

[0046] The viscosity measurements were carried out at 25° C., with theaid of a Contraves rotational viscometer equipped with an MS-R4 movingbody.

[0047] The measurements of the melting characteristics of the waxes wereperformed by DTA (differential thermal analysis) under the followingconditions: heating from 25 to 110° C., at a rate of 1° C./minute.

EXAMPLE 1 Composition According to the Invention

[0048] A lipstick having the following composition was prepared: Liquidparaffin 22.5% Lanolin oil 23.5% Isopropyl lanolate 24% Microcrystallinewax (nonpolar mineral 20% wax sold by Tisco, under the name “Tisco wax88”) Fillers (titanium oxide, mica) 3.5% Pigments 6.5%

[0049] These various ingredients were mixed at about 100° C. and themixture was introduced at the head of a twin-screw extruder. Theextrusion was carried out under the following conditions:

[0050] Inlet temperature: 100° C.

[0051] Outlet temperature: 30° C.

[0052] Residence time: about 3 minutes

[0053] Screw speed: 350 revolutions/min

[0054] A soft paste was obtained at the outlet which was presented inthe form of a single, stable and homogeneous phase and which wascollected with the aid of a brush for its application.

[0055] After application, this paste was considered to have satisfactoryqualities in relation to smoothness and sliding and did not have an oilytexture.

[0056] After six months of storage at 25° C. and 47° C., the followingviscosity measurements were obtained: Storage at 25° C.: 90 poises (9 Pa· s) Storage at 47° C.: 92 poises (9.2 Pa · s)

[0057] It was therefore observed that the composition according to theinvention retained practically the same viscosity after storage at roomtemperature or at a high temperature.

[0058] After six months of storage at 47° C., the appearance of thepaste did not change and could still be collected with the aid of abrush in order to be applied to the skin. The wax used in thiscomposition had a temperature at the onset of melting of the order of65-75° C. and a melting point of about 91-93° C.

EXAMPLE 2 Comparative Example

[0059] A lipstick having the following composition was prepared: Liquidparaffin 22.5% Lanolin oil 23.5% Isopropyl lanolate 24% Microcrystallinewax (nonpolar mineral 20% wax sold by RMC, under the name “Feruwax30540”) Fillers (titanium oxide, mica) 3.5% Pigments 6.5%

[0060] The lipstick was prepared in the same manner as in Example 1 anda soft paste was also obtained which was capable of being collected withthe aid of a brush.

[0061] After storage for two months, the following viscositymeasurements were obtained:

[0062] Storage at 25° C.: 80 poises (8 Pa.s)

[0063] Storage at 47° C.: 175 poises (17.5 Pa.s)

[0064] It was therefore observed that after only two months of storageat 47° C., a highly thickened composition was obtained which could nolonger come out of the applicator. The wax used, although having amelting point of about 69-71° C., had a temperature at the onset ofmelting of the order of 45-46° C.

[0065] Thus, the mere fact of choosing a wax whose melting point is ofthe order of the storage temperature is not sufficient in itself to makeit possible to maintain a constant viscosity for the composition andtherefore its suitable cosmetic properties.

What is claimed is:
 1. A cosmetic composition, in the form of a softpaste, which comprises a fatty phase in which one or more waxes arepresent, wherein at least 95% of said waxes have a temperature at theonset of melting which is greater than or equal to 50° C.
 2. Acomposition according to claim 1, in which 100% of said waxes have atemperature at the onset of melting which is greater than 50° C.
 3. Acomposition according to claim 1, in which said waxes have a temperatureat the onset of melting which is greater than 65° C.
 4. A compositionaccording to claim 1, wherein said waxes are selected from Carnauba wax,polyethylene waxes and microcrystalline waxes.
 5. A compositionaccording to claim 1, wherein said waxes represent 10-60% by weight ofsaid composition.
 6. A composition according to claim 5, wherein saidwaxes represent 15-35% by weight of said composition.
 7. A compositionaccording to claim 1, wherein said fatty phase comprises at least oneadditional fatty constituent that is an oil.
 8. A composition accordingto claim 7, wherein said at least one additional fatty constituent isselected from paraffin oil, liquid paraffin, perhydrosqualene, araraoil, sweet almond oil, calophyllum oil, palm oil, castor oil, avocadooil, jojoba oil, olive oil, cereal germ oil, esters of lanolic acid,oleic acid, lauric acid, stearic acid and myristic acid, alcohols,acetylglycerides, octanoates, decanoates and ricinoleates of alcoholsand of polyalcohols.
 9. A composition according to claim 8, wherein saidalcohols are selected from oleyl alcohol, linoleyl alcohol, linolenylalcohol, isostearyl alcohol and octyl dodecanol.
 10. A compositionaccording to claim 7, wherein said at least one additional fattyconstituent represents 40-90% by weight of the composition.
 11. Acomposition according to claim 10, wherein said at least one additionalfatty constituent represents 65-85% by weight of said composition.
 12. Acomposition according to claim 1, further comprising a pulverulentcolouring agent selected from carbon black, chromium oxides, ironoxides, ultramarines, manganese pyrophosphate, ferric blue, titaniumdioxide, pearlescent agents and organic colorants.
 13. A compositionaccording to claim 1, further comprising at least one inorganic ororganic pulverulent filler selected from talc, micas, kaolin, zincoxides, titanium oxides, calcium carbonates, magnesium carbonates,silica, spheric titanium dioxide, glass beads, ceramic beads, metallicsoaps derived from carboxylic acids having 8-22 carbon atoms,nonexpanded synthetic polymer powders, expanded powders and powders ofnatural organic compounds.
 14. A composition according to claim 13,wherein said natural organic compounds are cereal starches which may becrosslinked.
 15. A composition according to claim 1, which is in theform of a lip make-up or lip treatment product.
 16. A process forpreparing a composition in the form of a soft paste, said compositioncomprising a fatty phase in which one or more waxes are present, whereinat least 95% of said waxes have a temperature at the onset of meltingwhich is greater than or equal to 50° C., which process comprisesheating at least a portion of the constituents of said composition,including said waxes, to a temperature at which said waxes melt at leastpartially, adding the remaining constituents to said composition, andthen cooling the resulting mixture, wherein during at least part of saidcooling operation the resulting mixture is blended.
 17. A processaccording to claim 16, wherein said blending operation is carried out ina roll mill or in an extruder.
 18. A process according to claim 16,wherein said heating, adding or blending operations are carried out inone or more extruders which are arranged successively.
 19. A processaccording to claim 16, wherein said heating, adding, and blendingoperations are carried out in a single twin-screw extruder.
 20. A methodof improving the cosmetic qualities of a cosmetic composition duringstorage, comprising the step of including in said cosmetic compositionto improve the storage qualities, one or more waxes, wherein at least95% of said waxes have a temperature at the onset of melting which isgreater than or equal to 50° C.